It is usually said that moisture absorption of a radiation image conversion panel tends to occur easily, when a phosphor in the radiation image conversion panel formed by a vapor deposition method (hereinafter, referred to also as an evaporation type radiation image conversion panel) is not covered by binder and the like. In order to improve this, intensive studies have been made, in which moisture permeability of protective layers is lowered by reducing initial moisture as much as possible via heating of the phosphor, or moisture absorption is reduced as much as possible by providing an inert gas layer between the protective layer and the phosphor layer, but not much effect has been obtained (refer to Patent Documents 1 and 2, for example). Further, though the evaporation type radiation image conversion panel exhibits good properties such as sharpness and graininess in comparison to a coating type stimulable phosphor panel, further improved performance of these properties has been demanded.
(Patent Document 1) Japanese Patent O.P.I. Publication No. 2004-266876
(Patent Document 1) Japanese Patent O.P.I. Publication No. 2002-131496